With the aging population, the number of Americans with functional limitations will rise by over 300% by 2049 if the age-specific prevalence of major chronic conditions remains unchanged. While medical interventions can sometimes dramatically improve physical functioning, restoring functional abilities is unrealistic for many people. The focus shifts to preserving function, slowing its decline; and preventing secondary complications. Rehabilitation services, including physical therapy (PT) and occupational therapy (OT), are central to these efforts. Few studies have examined the outcomes of PT and OT as they are routinely practiced throughout communities in the United States. This project will use a longitudinal, nationwide survey of Medicare beneficiaries over and under age 65 (the 1994-2001 Medicare Current Beneficiary Surveys), linked with respondents' Medicare claims, to examine outcomes of PT and OT. A major change in Medicare payment policy -- the 1997 Balanced Budget Act, which tightened payments for rehabilitation services -- will serve as a "natural experiment" of conditions under which access to routine rehabilitation care is constrained. The proposed study aims to examine the association between the intensity of PT and OT services and likelihood of good outcomes, including lower rates of: self-reported functional decline; worsening overall health; activities of daily living (ADL) and instrumental ADL dependence; institutionalization; acute care hospitalization; injury prompting medical attention; decubitus ulcer development; purchase of assistive technology; social isolation; and death. The study will examine persons within five conditions: arthritis; stroke; acute myocardial infarction; chronic obstructive pulmonary disease; and lower extremity mobility problems, regardless of cause. Two inter-related hypotheses will guide this work: (1) increased intensity of PT and OT is associated with better outcomes; and (2) decreased access to PT and OT is associated with worse outcomes. These hypotheses will be tested using cross-sectional and longitudinal analyses; analytic techniques will include time series, propensity score, instrumental variable, and proportional hazards regression modeling. The primary outcome of the proposed study will be an assessment of the association of PT and OT, as routinely practiced nationwide and important outcomes of care.